Fingerprint identification panel and fingerprint identification circuit thereof

ABSTRACT

The present invention provides a fingerprint identification panel and the fingerprint identification circuit thereof, which comprise a gate driving circuit, a source driving circuit, and a detection circuit. The gate driving circuit is coupled to a plurality of gate lines, outputs a plurality of gate signals to the plurality of gate lines, and controls a state transition of the plurality of gate signals. The source driving circuit is coupled to a plurality of source lines. The detection circuit is coupled to the plurality of source lines or to a portion of the plurality of source lines. The detection circuit detects the levels of the plurality of signals on the coupled source lines when the state of the gate signal is changed and generates a plurality of detection signals.

FIELD OF THE INVENTION

The present invention relates generally to a panel and an identification circuit thereof, and particularly to a fingerprint identification panel and the fingerprint identification circuit thereof for identifying fingerprints.

BACKGROUND OF THE INVENTION

In the environment of mature touch technologies, fingerprint identification has become an indispensable authorization device for identity in the consumer electronics market. In particular, the fingerprint identification circuit designed below a display panel is appealing in the market. Under the keen competition, the consideration for production procedure and cost becomes important increasingly. Besides, to avoid the problems of thicker panels, higher costs, or more complicated processed caused by manufacturing sensing electrodes additionally, according to the China Publication Number CN104898314A and the US Publication Numbers US20070216657A1 and US20140333328A1, the technologies of using the existing electrodes as the fingerprint sensing electrodes are disclosed, respectively. Unfortunately, no matter which technology is adopted, additional fingerprint sensors should be fabricated, making the process complicated, the yield lowered, and the cost raised. It also makes fullscreen display panels not possible. For In-Cell processes, the usage of the touch sensors should be time-divided with the common electrode. Thereby, the control of the integrated chip on the panel becomes more complex.

Accordingly, the exemption of fabricating fingerprint sensors and the simplification of control are the issues to be solved currently.

SUMMARY

An objective of the present invention is to provide a fingerprint identification panel and the fingerprint identification circuit thereof, which detect the levels of a plurality of signals on a plurality of source lines of the panel for detecting the veins of a fingerprint. Thereby, the exemption of fabricating fingerprint sensors and the simplification of controlling fingerprint identification can be achieved.

The present invention discloses a fingerprint identification circuit, which comprises a gate driving circuit, a source driving circuit, and a detection circuit. The gate driving circuit is coupled to a plurality of gate lines of a panel, outputs a plurality of gate signals to the plurality of gate lines, and controls a state transition of the plurality of gate signals. The source driving circuit is coupled to a plurality of source lines of the panel. The detection circuit is coupled to the plurality of source lines or to a portion of the plurality of source lines. The detection circuit detects the levels of the plurality of signals on the coupled source lines when the state of the gate signal is changed and generates a plurality of detection signals.

The present invention discloses a fingerprint identification panel, which comprises a gate driving circuit, a source driving circuit, and a detection circuit. The gate driving circuit is coupled to a plurality of gate lines of a panel. The gate driving circuit outputs a plurality of gate signals to the plurality of gate lines and controls a state transition of the plurality of gate signals. The source driving circuit is coupled to a plurality of source lines of the panel. The detection circuit is coupled to the plurality of source lines or to a portion of the plurality of source lines. The detection circuit detects the levels of the plurality of signals on the coupled source lines when the state of the gate signal is changed and generates a plurality of detection signals.

The present invention discloses a fingerprint identification panel, which comprises a plurality of gate lines, a plurality of source lines, a gate driving circuit, a source driving circuit, and a detection circuit. The gate driving circuit is coupled to a plurality of gate lines. The gate driving circuit outputs a plurality of gate signals to the plurality of gate lines and controls a state transition of the plurality of gate signals. The source driving circuit is coupled to the plurality of source lines. The detection circuit is coupled to the plurality of source lines or to a portion of the plurality of source lines. The detection circuit detects the levels of the plurality of signals on the coupled source lines when the state of the gate signal is changed and generates a plurality of detection signals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic diagram of the fingerprint identification circuit according to the first embodiment of the present invention;

FIG. 2 shows a schematic diagram of the fingerprint identification circuit according to the second embodiment of the present invention;

FIG. 3 shows a schematic diagram of the fingerprint identification circuit according to the third embodiment of the present invention;

FIGS. 4A and 4B show schematic diagrams of identifying a fingerprint according to the first embodiment of the present invention;

FIGS. 5A and 5B show schematic diagrams of identifying a fingerprint according to the second embodiment of the present invention; and

FIG. 6 shows a schematic diagram of the levels of the detection signals for identifying a fingerprint according to the present invention.

DETAILED DESCRIPTION

In the specifications and subsequent claims, certain words are used for representing specific devices. A person having ordinary skill in the art should know that hardware manufacturers might use different nouns to call the same device. In the specifications and subsequent claims, the differences in names are not used for distinguishing devices. Instead, the differences in techniques as whole are the guidelines for distinguishing. In the whole specifications and subsequent claims, the word “comprising” is an open language and should be explained as “comprising but not limited to”. Besides, the word “couple” includes any direct and indirect electrical connection. Thereby, if the description is that a first device is coupled to a second device, it means that the first device is connected to the second device directly, or the first device is connected to the second device via other device or connecting means indirectly.

In order to make the structure and characteristics as well as the effectiveness of the present invention to be further understood and recognized, the detailed description of the present invention is provided as follows along with embodiments and accompanying figures.

Please refer to FIG. 1 , which shows a schematic diagram of the fingerprint identification circuit according to the first embodiment of the present invention. As shown in the figure, the fingerprint identification circuit comprises a gate driving circuit 10, a source driving circuit 20, a vein identification circuit 30, a switching circuit, and a detection circuit 50. According to an embodiment of the present invention, the switching circuit includes a plurality of switches TSW; the source driving circuit 20 includes a plurality of driving units 40; and the detection circuit 50 includes a plurality of comparators 51. In addition, the panel shown in the figure can be a fingerprint identification and display panel with displaying functionality or a fingerprint identification panel without displaying functionality. The panel includes a plurality of gate lines 11, a plurality of source lines 21, and a plurality of pixels R Each pixel P can include a transistor T. For the panel with displaying functionality, each pixel P can further include a common electrode (not shown in the figure), a liquid-crystal capacitor C_(LC), and a storage capacitor C_(S).

The gate driving circuit 10 is coupled to the plurality of gate lines 11 and outputs a plurality of gate signals G0, G1˜Gn to the plurality of gate lines 11. The plurality of gate lines 11 transmits the plurality of gate signals G0, G1˜Gn to the gates of the transistors T of the pixels P on each row, respectively. The gate driving circuit 10 can control the state transition of the plurality of gate signals G0, G1˜Gn for controlling the transistors T of the plurality of pixels P. The plurality of driving units 40 of the source driving circuit 20 is coupled to the plurality of source lines 21, respectively, and output a plurality of source driving signals S0, S1, S2, S3. S4, S5, S6, S7 to the plurality of source lines 21 according to a plurality of input signals I₀, I₁, I₂, I₃, I₄, I₅, I₆, I₇. The plurality of source lines 21 transmits the plurality of source driving signals S0˜S7 to the sources of the transistors T of the pixels P on each column, respectively. According to an embodiment of the present invention, the plurality of driving units 40 can be amplifiers, such as operational amplifiers. Besides, the source driving circuit 20 can further includes a plurality of digital-to-analog converters (not shown in the figure) for selecting one of a plurality of gamma voltages according to an input pixel signal, respectively, and outputting as the input signals I₀, I₁, I₂, I₃, I₄, I₅, I₆, I₇, respectively.

Moreover, the switching circuit is coupled between the plurality of source lines 21 and the source driving circuit 20 as well as the detection circuit 50. In other words, the switching circuit is coupled between the plurality of source lines 21 and the driving units 40 as well as the comparators 51. According to the first embodiment, the switching circuit is coupled to each source line 21. Thereby, the source driving signal S0—S7 are transmitted to the source lines 21 via the plurality of switches TSW of the switching circuit. The detection circuit 50 detects the signal levels of the source lines 21 through the switching circuit for detecting the changes in the signal of each source line 21 and generating a plurality of detection signals. The detection circuit 50 transmits the plurality of detection signals to the vein identification circuit 30. The vein identification circuit 30 is coupled to the detection circuit 50 for receiving the plurality of detection signals. Then it judges (identifies) the veins touching the panel according to the plurality of detection signals. The veins can be the veins of a finger touching the panel. According to the above description, the present invention can use the display panel as the fingerprint identification panel directly for detecting the signal levels of the source driving signals of the plurality of source lines 21 of the panel. Then the protruding veins and recess veins of a fingerprint can be identified. Nonetheless, the vein identification circuit 30 is not a necessary component for the embodiments of the present invention. Alternatively, the detection circuit 50 can output the plurality of detection signals (for example, via a register) to a host outside the panel. Then the host judges (identifies) the touch locations on the panel on which the protruding veins and recess veins of a fingerprint touch according to the plurality of detection signals. Thereby, the present invention may not use the vein identification circuit 30 to achieve the identification.

Please refer again to FIG. 1 . When the switching circuit is switched to the left side in the figure and connecting (turn on) the signal transmission paths between the source driving circuit 20 and the plurality of source lines 21, the source driving circuit 211 can output the source driving signals S0˜S7 to the plurality of source lines 21. Contrarily, when the switching circuit is switched to the right side in the figure and connecting the signal transmission paths between the detection circuit 50 and the plurality of source lines 21, the switching circuit cuts off the connection between the driving units 40 and the plurality of source lines 21. Thereby, the source driving signals S0˜S7 cannot be transmitted to the plurality of source lines 21. At this moment, the outputs of the source driving circuit 20 are floating as high impedance. Hence, the source driving signals S0˜S7 will not be output for reducing the power consumption of the source driving circuit 20. As the switching circuit is switched to the right side in the figure, the detection circuit 50 receives the source driving signal of each source line 21 for generating a plurality of detection signals TS0, TS2, TS3, TS4, TS5, TS6. The outputs of the detection circuit 50 are coupled to the vein identification circuit 30 and transmits the plurality of detection signals TS0˜TS6 to the vein identification circuit 30. In addition, according to the first embodiment, the switches TSW of the switching circuit are not limited to being switched concurrently.

In FIG. 1 , each comparator 51 of the detecting circuit 50 is coupled to two source lines 21 for receiving and comparing the signal levels of the two source lines 21, and hence generating and transmitting the detection signals TS0˜TS6 to the vein identification circuit 30. In other words, the vein identification circuit 30 acquires the signal levels of the source lines 21 according to the detection signals TS0˜TS6 for judging (identifying) the locations of the protruding veins and recess veins of a fingerprint. As shown in the figure, the first comparator 51 compares the signal levels of an Mth (the first) source line and an Nth (the second) source line for generating the first detection signal TS0; and the second comparator 51 compares the signal levels of the Nth (the second) source line and a Pth (the third) source line for generating the second detection signal TS1. The M, N, and P described above are positive integers.

It is noteworthy that if the driving units 40 of the source driving circuit 20 are operational amplifiers, the comparators in the detection circuit 50 can alternatively be formed by the driving units 40 in the source driving circuit 20 under some specific conditions such as when the operating voltages or current are approximate, because the terminal structure of a comparator is identical to an operational amplifier and an operational amplifier can act as a comparator. In other words, according to some embodiments of the present invention, switching the connection configuration of the inputs and outputs of the driving units 40 using the switching circuit or other switching devices can turn the driving units 40 to become comparators 51 of the detection circuit 50. By sharing a portion circuit of the source driving circuit 20 and the detection circuit 50, the device count of the fingerprint identification circuit can be further reduced.

In addition, the signal on the source lines 21 detected by the detection circuit 50 can be the source driving signal or the precharge signal. The source driving signal is the signal required for controlling the orientation of the liquid crystals in the pixel P while displaying; the precharge signal is the signal level for precharging the liquid-crystal capacitor before the source driving signal charges the liquid-crystal capacitor. Thereby, with precharging the pixel P, the charging time of the source driving circuit 20 on each pixel P can be reduced, or the output power consumption of the source driving circuit 20 can be lowered. Nonetheless, according to the first embodiment, it is not required that the fingerprint identification circuit must include the precharging mechanism for the pixel P. In other words, the signal of the source lines 21 detected by the detection circuit 50 may the source driving signal or the precharge signal. Accordingly, once the signal level on the source lines 21 is changed, the detection circuit 50 can generate the detection signal according to the signal level of the source lines 21. Then the vein identification circuit 30 or other processing circuits, such as the host described above, can identify the locations of the protruding veins and recess veins of a fingerprint according to the detection signal. According to an embodiment of the present invention, the source driving circuit 20 can include a circuit (not shown in the figure) for providing a predetermined initial voltage signal to the plurality of source lines 21. Hence, the detection circuit 50 can generate the detection signal according to the signal level of the source lines 21. The signal on the source lines 21 is the source line signal, for example, the source driving signal, the precharge signal, and the predetermined initial voltage signal.

Please refer to FIG. 2 , which shows a schematic diagram of the fingerprint identification circuit according to the second embodiment of the present invention. As shown in the figure, the difference between the second embodiment and the first one is that, according to the second embodiment, the two receiving terminals of the comparator 51 in the detection circuit 50 do not receive the signal from the source lines 21. Instead, one receiving terminal receives alternatively a first reference signal Ref1 or a second reference signal Ref2. The level of the first and second reference signals Ref1, Ref2 can be the signal level of each source line 21 in a specific state. For example, if the fingerprint identification circuit includes the precharging mechanism and when the source line 21 is transmitting the precharge signal to the pixel P, the source line 21 is at the level of the precharge signal. After a plurality of gate signals G0˜Gn are transmitted to a plurality of gate lines 11, the level of the precharge signal on the source line 21 affected by the coupling influence of the plurality of gate signals G0˜Gn being at the state transition (level changes) can be recorded. For example, when the gate signals G0˜Gn change from the low level to the high level (the rising edge) and the panel is not touched, the pulled-up or -down level of the precharge signal by the gate signals G0˜Gn are recorded. Then the pulled-up or -down level of the precharge signal can be used as the first reference signal Ref1 or the second reference signal Ref2.

Besides, the same measurement method can be used for recording the pulled-up or -down level of the precharge signal by the gate signals G0˜Gn when the gate signals G0˜Gn are at state transition (the rising edge) and the panel is touched. In other words, the level of the first and second reference signals Ref1, Ref2 can be set as the pulled-up or -down level of the precharge signal as the panel is touched.

When the process variation for the panel is negligible, all comparators 51 can adopt the same reference signal as the basis for comparison. Nonetheless, when the coupling effects of the plurality of gate signals G0˜Gn on both sides of the panel are different, the several comparators 51 on the left side can adopt the first reference signal Ref1 as the basis for comparison while the several comparators 51 on the right side can adopt the second reference signal Ref2 as the basis for comparison while, as shown in the second embodiment. Here, the second reference signal Ref2 is acquired by the measurement and recording as described above. Hence, the details will not be described again.

Please refer to FIG. 3 , which shows a schematic diagram of the fingerprint identification circuit according to the third embodiment of the present invention. As shown in the figure, the difference between the third embodiment and the second one is that, according to the third embodiment, each comparator 51 of the detection circuit 50 is coupled to a different reference signal, such as the first reference signal Ref1, the second reference signal Ref2, the third reference signal Ref3, and the fourth reference signal Ref4. In addition, the detection circuit 50 in FIG. 3 does not detect the state (change) of signal level on every source line. Namely, there is another source line between the Mth (the first) source line 211 coupled to the first comparator 51 and the Nth (the third) source line 213 coupled to the second comparator 51. Likewise, there is another source line between the Pth (the fifth) source line 211 coupled to the third comparator 51 and the Nth (the third) source line 213. Thereby, under cost consideration and without influencing fingerprint identification, two or more source lines can be placed between the Mth source line 211 and the Nth source line 213; two or more source lines can be placed between the Pth source line 215 and the Nth source line 213. According to the above description, the detection circuit 50 according to the third embodiment detects the signal levels of the coupled source lines 21 by coupling a portion of the plurality of source lines 21 through the switching circuit, which means that the switching circuit according to the third embodiment can be coupled to a portion of the plurality of source lines 21 and a portion of the driving units 40 in the source driving circuit 20, for generating the detection signal, and thus trading off between the overall cost and detection resolution.

Please refer again to FIG. 3 . According to the present embodiment, the first comparator 51 compares the signal level of the Mth (the first) source line 211 (the first) with the level of the first reference signal Ref1 for generating the first detection signal TS0; the second comparator 51 compares the signal level of the Nth (the third) source line 213 with the level of the second reference signal Ref2 for generating the second detection signal TS1; and the third comparator 51 compares the signal level of the Pth (the fifth) source line 215 with the level of the third reference signal Ref3 for generating the third detection signal TS2. The plurality of detection signals TS0, TS1, TS2 are all transmitted to the vein identification circuit 30 for judging the locations of the protruding veins and recess veins of a fingerprint.

Please refer to FIGS. 4A and 4B, which show schematic diagrams of identifying a fingerprint according to the first embodiment of the present invention. As shown in the figures, at time t1, the gate signal G0 changes to the high level, and the driving units 401, 402 of the source driving circuit 20 output the source driving signals S0, S1 to the source lines 21 for charging the pixels P. The waveforms of the source driving signals S0, S1 are the curves A1, A2 between time t1 and t2. The polarities of the source driving signals S0, S1 are different. After the gate signal G0 drives the pixels P on the first row of the panel, the gate signal G0 is changed from the high level to the low level at time t2.

In the period between time t2 and t3, the voltage levels of the signals on the source lines 21 continue to change. In the period between time t3 and t4, the voltage levels of the signals on the source lines 21 are kept constant and can be used as the initial voltage Vini-1 for fingerprint identification. At time t4, the gate signal G1 starts to change from the low level to the high level. At this moment, the switch TSW of the switching circuit is not closed yet, so the electrical paths between the source lines 21 and the driving units 401, 402 of the source driving circuit 20 are not connected. Thereby, the gate signal G1 will be coupled to the signals on the source lines 21 through the parasitic capacitance CAP1 and thus raising the initial voltage Vini-1 on the source lines 21. As the panel is not touched, the initial voltage Vini-1 is raised to the first voltage level Vdet1. When the source lines 21 (the panel) are touched, due to the inductive capacitance caused by an external conductor (the finger) touching the panel, the amplitude of the gate signal G1 raising the initial voltage Vini-1 through the coupling effect is reduced. Hence, the initial voltage Vini-1 is raised to the second voltage level Vdet2 at this time. In addition, according to FIG. 4B, the first voltage level Vdet1 is higher than the second voltage level Vdet2. A first voltage difference ΔVp between the first voltage level Vdet1 and the second voltage level Vdet2 corresponding to the states when the panel is not or is touched, respectively, appears. Accordingly, the detection circuit 50 detects the signal levels of the plurality of source lines 21 as the gate signals have state transition. By comparing the signal levels with the signals of adjacent source lines or comparing the signals of source lines with a reference signal, the corresponding detection signals will be given. Then the signal level of the source lines 21 will be known, and the locations of the protruding veins and recess veins of a fingerprint on the panel will be identified. The above parasitic capacitance CAP1 is located between the gate and the source of the transistor in the pixels P.

Furthermore, according to the embodiments from FIG. 1 to FIGS. 4A and 4B, the fingerprint identification circuit according to the present invention relies on no extra fingerprint sensing electrodes (the transmitting touch electrode TX and the receiving touch electrode RX). No extra fingerprint sensor is required, either. On the contrary, the fingerprint identification circuit according to the present invention identifies a fingerprint by the level changes of the gate signals G0˜Gn on the plurality of gate lines 11 of the panel and the signals of the plurality of source lines 21 (the source driving signal, the precharge signal, or the predetermined initial voltage signal). Thereby, the complexity of the driving circuit of the panel in processing the display and in fingerprint identification can be reduced.

To elaborate, please refer again to FIGS. 4A and 4B. While approaching time t4 or in the period between time t4 and t5, the switch TSW of the switching circuit connects the signal transmission path between the comparator 501 of the detection circuit 50 and the source line 21. The comparator 501 receives the initial voltage Vini-1 coupled with the gate signal G1. The voltage level of the initial voltage Vini-1 coupled with the gate signal G1 can be either the first voltage level Vdet1 or the second voltage level Vdet2. The comparator 501 compares the initial voltage Vini-1 coupled with the gate signal G1 to the level of the first reference signal Ref1 for generating the detection signal TS0. If the reference signal Ref1 is the signal level of the source line 21 when the touch panel is not touched, as a conductor (the finger) touches the source line 21 coupled with the comparator 501, the first reference signal Ref1 is higher than the second voltage level Vdet2. Thereby, the detection signal TS0 output by the comparator 501 can be at the high level. Then, a high-leveled detection signal TS0 means that the source line coupled with the comparator 501 is touched by a conductor. The vein identification circuit 30 can judge that the source line coupled with the comparator 501 is touched by a conductor, meaning that the locations of the protruding veins of a finger can be judged (identified). Alternatively, the vein identification circuit 30 can generate a vein identification signal for another processing circuit, such as the host described above. Then the processing circuit judges the locations of the protruding veins and recess veins of a fingerprint.

At time t5, the switching circuit cuts off the electrical coupling path between the detection circuit 50 and the source line 21 and connects the electrical coupling path between the source driving circuit 20 and the source line 21. Thereby, the source driving circuit 20 outputs the source driving signal S0 and starts to charge the pixel P, and the polarity of the source driving signal S0 is inverted from the positive polarity between time t1 and t2 to the negative polarity between time t5 and t6. In addition, as shown in FIG. 4B, the polarity of the other signal (the one below the t-axis) is opposite to the polarity of the above signal. Between time t4 and t5, there is a second voltage difference ΔVn on the signal between the source line being touched or not touched by a conductor. The rest detection method is the same as the above. According to an embodiment of the present invention, the switching circuit can be controlled by the gate driving circuit 10, which can generate the switching signal according to the state of the gate signals G0˜Gn. According to another embodiment of the present invention, another circuit can be adapted to generate the switching signal according to the state of the gate signals G0˜Gn for controlling the switching circuit. It is not limited to the gate driving circuit 10.

Please refer to FIGS. 5A and 5B, which show schematic diagrams of identifying a fingerprint according to the second embodiment of the present invention. As shown in the figures, according to the present embodiment, when the gate signal. G0 changes from the high level to the low level, the signal level of the source line 21 is detected. In other words, while approaching time t2, the switching circuit first cuts off the electrical connection paths between the plurality of source lines 21 and the source driving circuit 20 and connects the electrical connecting paths between the source lines 21 and the detection circuit 50. In the period between time t2 and t3, when the panel is not touched, the voltage level Vin-2 of the source line 21 will be pulled down to the third voltage level Vdet3 due to the coupling with the gate signal G0 through the parasitic capacitance CAP1. When the source line 21 of the panel is touched, the voltage level Vini-2 will be pulled down to the fourth voltage level Vdet4. According to FIG. 5B, the third voltage level Vdet3 is lower than the fourth voltage level Vdet4 and the difference therebetween is a second voltage difference ΔVn. Next, the operation after time t3 is as the description for the embodiment in FIGS. 4A and 4B. The difference between the embodiment in FIGS. 4A and 4B and the one in FIGS. 5A and 5B is on fingerprint identification according to the falling or rising edge of the gate signals G0, G1. In other words, although the embodiments from FIG. 1 to FIGS. 5A and 5B are not completely the same, they are all based on the signal level change on the source lines 21 due to coupling of the gate signals G0˜Gn to the source lines 21 through the parasitic capacitance CAP1. Then fingerprint identification is achieved according to the signal level on the source lines 21. Thereby, the present invention is not limited to the coupling relation between the plurality of source lines 21 and the comparators 51 of the detection circuit 50; the present invention is not limited to the configuration of the reference signals Ref1, Ref2, either.

Please refer to FIG. 6 , which shows a schematic diagram of the levels of the detection signals for identifying a fingerprint according to the present invention. As shown in the figure, the dashed circle is the touch location by a finger. At the locations of the panel where the protruding veins of a finger touch, the level of the detection signal output by the comparator 51 is high (1); at the locations of the panel where the protruding veins of a finger does not touch, the level of the detection signal output by the comparator 51 is low (0). The bottom right figure in FIG. 6 is a schematic diagram of the comparator 51 comparing the signals on the source lines 21 to the reference signal; the bottom left figure in FIG. 6 is a schematic diagram of the comparator 51 comparing the signals on two source lines 21.

To sum up, the present invention discloses a fingerprint identification circuit, which comprises a gate driving circuit, a source driving circuit, and a detection circuit. The gate driving circuit is coupled to a plurality of gate lines of a panel, outputs a plurality of gate signals to the plurality of gate lines, and controls state transition of the plurality of gate signals. The source driving circuit is coupled to a plurality of source lines of the display panel. The detection circuit is coupled to the plurality of source lines or to a portion of the plurality of source lines. The detection circuit detects the levels of the plurality of signals on the coupled source lines when the gate signals change states and generates a plurality of detection signals. Accordingly, the fingerprint identification circuit according to the present invention relies on no extra fingerprint sensing electrodes (the transmitting touch electrode TX and the receiving touch electrode RX). No extra fingerprint sensor is required, either. The detection circuit according to the present invention identifies a fingerprint by the level changes of the gate signals on the plurality of gate lines of the panel and the signals of the plurality of source lines (the source driving signal, the precharge signal, or the predetermined initial voltage signal). Thereby, the complexity of the driving circuit of the panel in processing the display and in fingerprint identification can be reduced. 

The invention claimed is:
 1. A fingerprint identification circuit, applied for fingerprint identification, said fingerprint identification circuit comprising: a gate driving circuit, coupled to a plurality of gate lines of a panel, outputting a plurality of gate signals to said plurality of gate lines, and controlling a rising edge or a falling edge of said plurality of gate signals; a source driving circuit, coupled to a plurality of source lines of said panel; a detection circuit, coupled to said plurality of source lines or a portion of said plurality of source lines, detecting the level of a plurality of signals on said plurality of source lines coupled to said detection circuit, and generating a plurality of detection signals for fingerprint identification; and a switching circuit, coupled between said plurality of source lines or said portion of said plurality of source lines and said detection circuit; wherein said gate signal on said plurality of gate lines has said rising edge or falling edge, said rising edge pulls up the level of said plurality of signals on said plurality of source lines coupled to said detection circuit or said falling edge pulls down the level of said plurality of signals on said plurality of source lines coupled to said detection circuit, and said detection circuit detects said pulled-up level or said pulled-down level of said plurality of signals on said plurality of source lines and generates said plurality of detection signals for fingerprint identification, said plurality of signals on said plurality of source lines are isolated from a plurality of output signals of said source driving circuit when said gate signal has said rising edge or falling edge.
 2. The fingerprint identification circuit of claim 1, wherein said switching circuit is coupled between said plurality of source lines or said portion of said plurality of source lines and said source driving circuit as well as said detection circuit, and said detection circuit detects the level of said plurality of signals of said plurality of source lines coupled to said detection circuit when said switching circuit cuts off the connection between said plurality of source lines or said portion of said plurality of source lines and said source driving circuit.
 3. The fingerprint identification circuit of claim 2, wherein said source driving circuit includes a plurality of driving units coupled to said plurality of source lines, respectively, for outputting a plurality of source driving signals to said plurality of source lines; said plurality of driving units or a portion of said plurality of driving units are coupled to said switching circuit; and said detection circuit detects the level of said plurality of signals of said plurality of source lines coupled to said detection circuit when said switching circuit cuts off the connection between said plurality of driving units and said plurality of source lines or between said portion of said plurality of driving units and said portion of said plurality of source lines.
 4. The fingerprint identification circuit of claim 3, wherein said source driving circuit outputs said plurality of source driving signals to said plurality of source lines when said switching circuit cuts off the connection between said plurality of source lines or said portion of said plurality of source lines and said detection circuit.
 5. The fingerprint identification circuit of claim 1, wherein when said detection circuit detects the level of said plurality of signals of said plurality of source lines coupled to said detection circuit, the signal of said plurality of source lines coupled to said detection circuit is the sum of a source driving signal, a precharge signal, or a predetermined initial voltage signal coupled with said gate signal.
 6. The fingerprint identification circuit of claim 1, and further comprising a vein identification circuit, coupled to said detection circuit, and identifying a location of protruding veins of a conductor according to said plurality of detection signals.
 7. The fingerprint identification circuit of claim 1, wherein said detection circuit includes a plurality of comparators, coupled to said plurality of source lines or said portion of said plurality of source lines, generating said plurality of detection signals, a first comparator of said plurality of comparators comparing the signal level of an Mth source line with the signal level of an Nth source line for generating a first detection signal of said plurality of detection signals, a second comparator of said plurality of comparators comparing the signal level of said Nth source line with the signal level of a Pth source line for generating a second detection signal of said plurality of detection signals, and M, N, P being positive integers.
 8. The fingerprint identification circuit of claim 1, wherein said detection circuit includes a plurality of comparators, coupled to said plurality of source lines or said portion of said plurality of source lines, generating said plurality of detection signals, including a first comparator, a second comparator, and a third comparator, said first comparator comparing the signal level of an Mth source line with the level of a reference signal for generating a first detection signal of said plurality of detection signals, said second comparator comparing the signal level of an Nth source line with the level of said reference signal for generating a second detection signal of said plurality of detection signals, said third comparator comparing the signal level of a Pth source line with the level of said reference signal for generating a third detection signal of said plurality of detection signals, and M, N, P being positive integers.
 9. The fingerprint identification circuit of claim 1, wherein said detection circuit includes a plurality of comparators, coupled to said plurality of source lines or said portion of said plurality of source lines, generating said plurality of detection signals, including a first comparator, a second comparator, and a third comparator, said first comparator comparing the signal level of an Mth source line with the level of a first reference signal for generating a first detection signal of said plurality of detection signals, said second comparator comparing the signal level of an Nth source line with the level of a second reference signal for generating a second detection signal of said plurality of detection signals, said third comparator comparing the signal level of a Pth source line with the level of a third reference signal for generating a third detection signal of said plurality of detection signals, and M, N, P being positive integers.
 10. The fingerprint identification circuit of claim 7, wherein said Mth source line, said Nth source line, and said Pth source line are arranged in order and adjacent to each other.
 11. The fingerprint identification circuit of claim 8, wherein said Mth source line, said Nth source line, and said Pth source line are arranged in order and adjacent to each other.
 12. The fingerprint identification circuit of claim 7, wherein said Mth source line, said Nth source line, and said Pth source line are spaced by one or more source line.
 13. The fingerprint identification circuit of claim 8, wherein said Mth source line, said Nth source line, and said Pth source line are spaced by one or more source line.
 14. A fingerprint identification panel, applied for fingerprint identification, comprising: a plurality of gate lines; a plurality of source lines; a gate driving circuit, coupled to said plurality of gate lines, outputting a plurality of gate signals to said plurality of gate lines, and controlling a rising edge or a falling edge of said plurality of gate signals; a source driving circuit, coupled to said plurality of source lines; a detection circuit, coupled to said plurality of source lines or a portion of said plurality of source lines, detecting the level of a plurality of signals on said plurality of source lines coupled to said detection circuit, and generating a plurality of detection signals for fingerprint identification; and a switching circuit, coupled between said plurality of source lines or said portion of said plurality of source lines and said detection circuit; wherein said gate signal on said plurality of gate lines has said rising edge or falling edge, said rising edge pulls up the level of said plurality of signals on said plurality of source lines coupled to said detection circuit or said falling edge pulls down the level of said plurality of signals on said plurality of source lines coupled to said detection circuit, and said detection circuit detects said pulled-up level or said pulled-down level of said plurality of signals on said plurality of source lines and generates said plurality of detection signals for fingerprint identification, said plurality of signals on said plurality of source lines are isolated from a plurality of output signals of said source driving circuit when said gate signal has said rising edge or falling edge.
 15. The fingerprint identification panel of claim 14, wherein said switching circuit is coupled between said plurality of source lines or said portion of said plurality of source lines and said source driving circuit as well as said detection circuit, and said detection circuit detects the level of said plurality of signals of said plurality of source lines coupled to said detection circuit when said switching circuit cuts off the connection between said plurality of source lines or said portion of said plurality of source lines and said source driving circuit.
 16. The fingerprint identification panel of claim 15, wherein said source driving circuit includes a plurality of driving units coupled to said plurality of source lines, respectively, for outputting a plurality of source driving signals to said plurality of source lines; said plurality of driving units or a portion of said plurality of driving units are coupled to said switching circuit; and said detection circuit detects the level of said plurality of signals of said plurality of source lines coupled to said detection circuit when said switching circuit cuts off the connection between said plurality of driving units and said plurality of source lines or between said portion of said plurality of driving units and said portion of said plurality of source lines.
 17. The fingerprint identification panel of claim 16, wherein said source driving circuit outputs said plurality of source driving signals to said plurality of source lines when said switching circuit cuts off the connection between said plurality of source lines or said portion of said plurality of source lines and said detection circuit.
 18. The fingerprint identification panel of claim 14, wherein when said detection circuit detects the level of said plurality of signals of said plurality of source lines coupled to said detection circuit, the signal of said plurality of source lines coupled to said detection circuit is the sum of a source driving signal, a precharge signal, or a predetermined initial voltage signal coupled with said gate signal.
 19. The fingerprint identification panel of claim 14, and further comprising a vein identification circuit, coupled to said detection circuit, and identifying a location of protruding veins of a conductor according to said plurality of detection signals.
 20. The fingerprint identification panel of claim 14, wherein said detection circuit includes a plurality of comparators, coupled to said plurality of source lines or said portion of said plurality of source lines, generating said plurality of detection signals, a first comparator of said plurality of comparators comparing the signal level of an Mth source line with the signal level of an Nth source line for generating a first detection signal of said plurality of detection signals, a second comparator of said plurality of comparators comparing the signal level of said Nth source line with the signal level of a Pth source line for generating a second detection signal of said plurality of detection signals, and M, N, P being positive integers.
 21. The fingerprint identification panel of claim 14, wherein said detection circuit includes a plurality of comparators, coupled to said plurality of source lines or said portion of said plurality of source lines, generating said plurality of detection signals, including a first comparator, a second comparator, and a third comparator, said first comparator comparing the signal level of an Mth source line with the level of a reference signal for generating a first detection signal of said plurality of detection signals, said second comparator comparing the signal level of an Nth source line with the level of said reference signal for generating a second detection signal of said plurality of detection signals, said third comparator comparing the signal level of a Pth source line with the level of said reference signal for generating a third detection signal of said plurality of detection signals, and M, N, P being positive integers.
 22. The fingerprint identification panel of claim 14, wherein said detection circuit includes a plurality of comparators, coupled to said plurality of source lines or said portion of said plurality of source lines, generating said plurality of detection signals, including a first comparator, a second comparator, and a third comparator, said first comparator comparing the signal level of an Mth source line with the level of a first reference signal for generating a first detection signal of said plurality of detection signals, said second comparator comparing the signal level of an Nth source line with the level of a second reference signal for generating a second detection signal of said plurality of detection signals, said third comparator comparing the signal level of a Pth source line with the level of a third reference signal for generating a third detection signal of said plurality of detection signals, and M, N, P being positive integers.
 23. The fingerprint identification panel of claim 20, wherein said Mth source line, said Nth source line, and said Pth source line are arranged in order and adjacent to each other.
 24. The fingerprint identification panel of claim 21, wherein said Mth source line, said Nth source line, and said Pth source line are arranged in order and adjacent to each other.
 25. The fingerprint identification panel of claim 20, wherein said Mth source line, said Nth source line, and said Pth source line are spaced by one or more source line.
 26. The fingerprint identification panel of claim 21, wherein said Mth source line, said Nth source line, and said Pth source line are spaced by one or more source line. 